Prosodic and Segmental Aspects of Speech Perception with the House/3M Single-Channel Implant

Abstract

Four adult users of the House/3M single-channel cochlear implant were tested for their ability to label question and statement intonation contours (by auditory means alone) and to identify a set of 12 intervocalic consonants (with and without lipreading). Nineteen of 20 scores obtained on the question/statement task were significantly better than chance. Simplifying the stimulating waveform so as to signal fundamental frequency alone sometimes led to an improvement in performance. In consonant identification, lipreading alone scores were always far inferior to those obtained by lipreading with the implant. Phonetic feature analyses showed that the major effect of using the implant was to increase the transmission of voicing information, although improvements in the appropriate labelling of manner distinctions were also found. Place of articulation was poorly identified from the auditory signal alone. These results are best explained by supposing that subjects can use the relatively gross temporal information found in the stimulating waveforms (periodicity, randomness and silence) in a linguistic fashion. Amplitude envelope cues are of significant, but secondary, importance. By providing information that is relatively invisible, the House/3M device can thus serve as an important aid to lipreading, even though it relies primarily on the temporal structure of the stimulating waveform. All implant systems, including multi-channel ones, might benefit from the appropriate exploitation of such temporal features.

Neurophysiologic Bases of Speech Discrimination

“…The perception of short-duration spectral changes, as in /da/-/ga/, is particularly vulnerable to disruption (Elliott et al, 1989;Elliott & Hammer, 1988;Phillips & Farmer, 1990;Rosen, Walliker, Brimacombe, & Edgerton, 1989;Tallal, 1981;Tallal et al, 1985;Turner & Robb, 1987). In contrast, differences in the duration of a spectral transition are more easily perceived (Auerbach, Allard, Naeser, Alexander, & Albert, 1982;Rosen et al, 1989).…”

Performance of Patients Using Different Cochlear Implant Systems: Effects of Input Dynamic Range

“…This type of outcome has been reported for many years (e.g., Blamey, Dowell, Brown, Clark & Seligman, 1987;Dorman, Dankowski, McCandless & Smith, 1990;Rosen, Walliker, Brimacombe & Edgerton, 1989). Over time, both scores for speech material that emphasized temporal/envelope cues and scores for material that emphasized spectral cues have improved.…”

“…Over time, both scores for speech material that emphasized temporal/envelope cues and scores for material that emphasized spectral cues have improved. However, because temporal/envelope information could be received at a modest level by patients fit with a single channel implant (Rosen et al, 1989), it is receipt of spectral information that has changed the most over time.…”

Audio-visual consonant recognition with the 3M/House cochlear implant

“…This procedure bypassed the frequency characteristics of the microphone, eliminated body-baffle effects, and may have provided the subjects with an unfamiliar signal spectrum, but was used to control as much of the variability associated with the signal input as possible . This procedure is similar to the direct-connect condition used by Rosen, Walliker, Brimacombe, and Edgerton (13) . Stimuli in the V and AV conditions were directed to 48 .5 cm diagonal color video monitor.…”

“…Pooled consonant confusion matrix for auditory-visual condition. A, V, and AV conditions by normal-hearing listeners, hearing-impaired hearing aid wearers, and single-channel cochlear implant users (1,3,7,9,10,11,13,16,17) . Although direct predictions to conversational speech cannot be drawn from these results, the improvements in consonant scores in the AV condition suggest that the implant should help these subjects perform well in everyday speechreading situations having more content and contextual cues .…”